1. Field
This disclosure relates to establishing sessions in communications networks, more particularly to exchange of capabilities between endpoints during session establishment.
2. Background
Current communications systems use endpoints, such as gateways, to establish communication between two users. For an example, a User 1 dials or otherwise calls into a first endpoint that gives the user access to a communication network, such as a multimedia communication network in compliance with the ITU (International Telecommunications Union) recommendation H.323. The first endpoint then takes the information, such as the number dialed or an address provided by the user, and uses it in establishing a call across the network.
Generally, the call across the network will involve another endpoint, the terminating endpoint, which would then connect with User 2, the call recipient. During the call setup between the two endpoints, there is typically a capabilities exchange between the two. This allows the calling endpoint to determine in what format or with what signals the data should be exchanged with the called endpoint. Similarly, it allows the called endpoint the ability to determine in what format or with what signals the data may be exchanged.
In current systems, this capability exchange is performed, even if the two endpoints have previously interacted. For example, User 1 places a call to User 2 through endpoint 1 and endpoint 2. After this call, endpoint 1 ‘knows’ the capabilities of endpoint 2. However, in a different call, where User 3 calls User 4, using the same two endpoints 1 and 2, the capability exchange still takes place. This would typically not be required, as the end points capability may not change too often, and elimination of this exchange would reduce network bandwidth consumption, as it would reduce the amount of message traffic on the network related to call setups.